<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
    new Promise((resolve, reject)=>{
        setTimeout(()=>{
            resolve('1')
        },1000)
    }).then(data=>{
        console.log(data)
        return new Promise((resolve, reject) => {
            setTimeout(()=>{
                resolve('2')
            },1000)
        })
    }).then(data=>{
        console.log(data)
        return new Promise((resolve, reject) => {
            setTimeout(()=>{
                resolve('3')
            },1000)
        })
    }).then(data=>{
        console.log(data)
    })


</script>
</html>